Merge pull request #3427 from chasinglogic/files-ninfo

Improve threading performance by sharing NodeInfo across threads

3 files changed, 11 insertions, 10 deletions

diff --git a/src/CHANGES.txt b/src/CHANGES.txt
index 3efb734..6450da5 100755
--- a/src/CHANGES.txt
+++ b/src/CHANGES.txt
@@ -6,9 +6,11 @@
 
 RELEASE  VERSION/DATE TO BE FILLED IN LATER
 
-  From John Doe:
+  From Mathew Robinson:
 
-    - Whatever John Doe did.
+    - Improved threading performance by ensuring NodeInfo is shared
+      across threads. Results in ~13% improvement for parallel builds
+      (-j# > 1) with many shared nodes.
 
 
 RELEASE 3.1.1 - Mon, 07 Aug 2019 20:09:12 -0500
diff --git a/src/engine/SCons/Node/FSTests.py b/src/engine/SCons/Node/FSTests.py
index 72eaba7..eddfdf0 100644
--- a/src/engine/SCons/Node/FSTests.py
+++ b/src/engine/SCons/Node/FSTests.py
@@ -2545,11 +2545,10 @@ class FileTestCase(_tempdirTestCase):
 
             def get_ninfo(self):
                 """ mocked to ensure csig will equal the filename"""
-                try:
-                    return self.ninfo
-                except AttributeError:
-                    self.ninfo = FakeNodeInfo(self.name, self.timestamp)
+                if self.ninfo is not None:
                     return self.ninfo
+                self.ninfo = FakeNodeInfo(self.name, self.timestamp)
+                return self.ninfo
 
             def get_csig(self):
                 ninfo = self.get_ninfo()
diff --git a/src/engine/SCons/Node/__init__.py b/src/engine/SCons/Node/__init__.py
index 572465f..daf79ba 100644
--- a/src/engine/SCons/Node/__init__.py
+++ b/src/engine/SCons/Node/__init__.py
@@ -614,6 +614,7 @@ class Node(object, with_metaclass(NoSlotsPyPy)):
         self._func_rexists = 1
         self._func_get_contents = 0
         self._func_target_from_source = 0
+        self.ninfo = None
 
         self.clear_memoized_values()
 
@@ -1131,11 +1132,10 @@ class Node(object, with_metaclass(NoSlotsPyPy)):
         return ninfo
 
     def get_ninfo(self):
-        try:
-            return self.ninfo
-        except AttributeError:
-            self.ninfo = self.new_ninfo()
+        if self.ninfo is not None:
             return self.ninfo
+        self.ninfo = self.new_ninfo()
+        return self.ninfo
 
     def new_binfo(self):
         binfo = self.BuildInfo()